Fix fontFamilies No returnvalues sections (#581)

Co-authored-by: George Peter Banyard <[email protected]>

Author: thinkverse

reference/ui/functions/ui.draw.text.font.fontfamilies.xml

@@ -24,6 +24,13 @@
   &no.function.parameters;
  </refsect1>
 
+ <refsect1 role="returnvalues">
+  &reftitle.returnvalues;
+  <para>
+   Returns an &array; of valid font families for the current system.
+  </para>
+ </refsect1>
+
 </refentry>
 
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